Recording system



R. R. CHAPPELL RECORDING SYSTEM 2f U/ws Y May 16, 1944.

Original Filed May 9, 1940 3 Sheets-Sheet 1 wmY w, RMH. ma m WM m vf MMs. EL

Ml? 16, 1944. R. R cHAPPELl. l 2,348,711

RECORDING SYSTEM Original Filed lay 9, 1940 3 Sheets-Sheet 2 wzl I l.ulm l l l I l l 1 l l I l l g: 5 s' vs/ SE I mveNToR fak/n@ (7M/WeBMW/15M.

ATTORNEY.

Examiner 3 Sheets-Sheet 3 W mutua@ AIII. www. uh 4 n N llvllll.

rr. n0 N rr. DA EL rr. .EL D S S 0 R C INVENToR d/,v K (a/ape# ATTORNEY.

R. R. CHAPPELL.

RECORDING SYSTEM Original Filed lay 9, 1940 May 1s, 1944. f

Patented May 16, 1944 RECORDING SYSTEM Ralph R. Chappell, Richmond, Va.,assignor to Bendix Aviation Corporation, Bendix, N. J., a

corporation of Delaware Original application May 9,

1940, Serial No.

334,286. Divided and this application October 21, 1942, Serial No.462,851

1 Claim.

The present invention relates to recording apparatus and moreparticularly to a recording device of the type employing a photoelectriccell and a beam of light which is interrupted by means of a pointer ofan indicating instrument f.

indicating the quantity which is to be recorded. and is a division ofcopending application Serial No. 334,286 filed May 9, 1940.

One of the objects of the present invention is to provide a novelrecording device which will accurately and faithfully record indicationsrepresentative of different variable conditions which are to berecorded.

Another object is to provide a novel recording device adapted to make awritten or printed record of variable conditions in a manner that can bereadily interpreted.

A further object of the invention resides in the provision of a uniquephotoelectric circuit which, in combination with a novel marking system,gives a precise record of variable conditions, and in the provision of acompact mechanical arrangement incorporating mechanical and electronicelements in a novel structure to give a clear record of variableconditions which it is desired to measure and record.

Theabove and other objects and advantages of the invention will appearmore fully hereinafter from a consideration of the detailed descriptionwhich follows, taken together with the accompanying drawings wherein oneembodiment of the invention is illustrated. It is to be eX- presslyunderstood, however, that the drawings are for purposes of illustrationonly and are not to be construed as defining the limits of theinvention, reference being had for this purpose to the appended claim.

In the drawings wherein like reference characters refer to like partsthroughout the several views:

Fig. 1 is a plan view of one embodiment of the present invention;

Fig. 2 is a front elevation with certain parts in section, of therecording device shown in Fig. 1;

Fig. 3 is a cross-sectional view taken along the line 3-3 of Fig. 2;

Fig. 4 is a cross-sectional view taken along the line 4 4 of Fig. 2; and

Fig. 5 is a diagrammatic showing of the mechanical and electricalcircuits of the embodiment of the invention shown in Figs. 1 4.

The device of the present invention has utility in the general art ofrecording, but is particularly intended for use on the ground inconjunction with a radio transmitter, which is carried from the groundthrough the atmosphere by a free balloon and which, as it ascends, willtransmit signals characteristic of atmospheric conditions at differentelevations. Such a transmitter is usually called a radio meteorograph ora radiosonde and is employed particularly in aviation to determineflight conditions and in general meteorographic service to determineatmospheric conditions at particular stations.

In one form of meteorograph, a carrier frequency of about sixty-livemegacycles is modulated byA a frequency on the order of one megacycle.which modulating frequency is interrupted at different audio-frequenciesrepresentative of different values of temperature, relative humidity,altitude, etc. These signals may be received and recorded by the use ofa device made in accordance with the present invention and interpretedby certain rules which it is not necessary to consider at this time.

Having particular reference to Figs. 1 and 2, the recording device I0 iscomposed of a rigid frame, having metal end-plates II and I2, a basemember I3, and a transverse supporting rod I 4. A printing roll memberI5 is mounted between end-plates II and I2 and its shaft I6, whichpasses through holes in end members II and I2, terminates in gears I1and I8, which are keyed to shaft I6. Roll member I5 has a smooth,cylindrical surface upon which is a helical ridge or projection I9 alongits length. Printing roll member I5 is driven through a suitable geartrain by motor 20, shown in phantom in Fig. 2. A gear 2i is keyed to theshaft of motor 20 and drives gear I8 through a suitable train. The gearI8 meshes with a larger gear 22, which is fixed to shaft 23, to which isalso fixed a disc member 24 carrying a light source, designatedgenerally as 25. Gear I'I, being affixed to shaft I6 with gear I8, turnstherewith and meshes with gear 26, which is fixed to shaft 21 carryingrotatable disc 28 and the photoelectric cell, designated generally at29.

A carriage, designated as 30, is rockably mounted between end-plates IIand I2 upon a shaft 3| which is loosely carried by end-plates Il and I2in any suitable bearings. As shown more clearly in Figs. 3 and 4,carriage 30 is pivoted to move about shaft 3l and carries transverseframe member 32 which is rigidly connected at its ends to verticalrocker arms 33 and 34, which are mounted t0 rotate or oscillate aboutshaft 3i and carry the entire carriage member 30. Fixedly mounted withrespect to arms 33 and 34 are horizontally projecting arms 35, to whichare attached, by pivotal means 35, additional arms 31 which, at theirouter ends, are attached to a transverse tapper bar 38, normally heldslightly spaced above the raised portion or projection I9 of roll I5 bymeans of spring members 39. Vertical end members 45 are rigidly attachedto frame member 32 so as to form a part of carriage 30 rockable aboutshaft 3| and these end members 48 are turned outwardly at their forwardend 4I to carry freely rotating spindles 42, upon which a copy ribbon,such as typewriter ribbon, is threaded, as will be later described.Transversely of end members 45, there is placed a rigid bridge member 43which carries the ribbon rolls 44, and also depending arms 45, which arerigidly attached thereto in any conventional manner, and havehorizontally projecting edges forming stop members 45. Horizontallyextending stop members 48 contact the underside of arms 35 in order tolimit downward rotative motion of arms 35. Spring members 39 areprevented from rotating arms 31 clockwise with respect to arms 35 bymeans of the stop members 41, which are integrally connected to the endsof arms 31 and extend horizontally inwardly a sumcient distance to bearupon the top surface oi' arms 35.

It will be seen, therefore (from Fig. 3), that arms 35 and 31 can berocked clockwise without relative angular motion, but that arms 31 andtapper bar 38 can be rotated counter-clockwise with respect to arm 35through an arc limited by stop members 41 at one end and projection I9of printing roll I at the other end of its travel.

Rocker arm 34 has an integral extension 48 which terminates in a camfollower 49 in engagement with heart-shaped cam member 50. Cam member 50is rigidly fixed to shaft 21 and rotated at constant speed by means ofgear 26. Also carried on shaft 3|, adjacent end-plate II, is a platemember 5I to which is rigidly connected a transversely extending stopmember 52. One end of a spring member 53 is connected to the platemember 5| which has a vertically extending slot 54 therein. Lying inparallel relation to plate member 5I, and between it and end member II,is segmental gear member 55 to which is attached the other end of spring53 by means of a lug 58 extending through slot 54 of plate 5I. Initialadjustment of bar member 38,

to be slightly raised above projection I9 of printing roll I5, isaccomplished -by adjusting screw members 51 with respect to stop member52 against the tension of spring 53 carried by rocker arm 34. It will bereadily seen then, that once every revolution of cam 50, carriage 30,including tapper bar 38, will be rocked clockwise for an intervaldepending on the characteristics of cam 55, so that an operator mayinspect the marking made by tapper bar 38 upon sheet 59, and thus obtaina quick check on the proper operation of the recording device.

A second segmental gear member 58 is pivoted upon shaft I5, extendingthrough end-plate II and fixedly connected by means of a key to handlemember 50 which lies closely adjacent endplate II. Upon pulling handle5I) to the left, as rshown in Fig. 4, the whole carriage assembly 30, aswell as plate 5|, and gear segment 55, will be rocked clockwise, andsimultaneously segment 58 will be rocked counter-clockwise, in order tofacilitate a change of record sheet 59, and for inspection purposes, aswill lbecome apparent as the description proceeds.

In order to prevent rocking motion, due to the engagement of extension48 with cam 5U, from also causing rotation of gear segments 55 and 58,handle 60 is normally held in place by a latch member 8| which engageswith the notch or de- 5 tent 82 in handle member 58.

Frame member 32 carries two electromagnets, indicated generally at 83,which are rigidly suspended by any conventional means, such as nuts and-bolts 84. An armature 55, carried by extensions of arms 35, ispositioned directly beneath electromagnets 53, and is adapted to beattracted upwardly upon energization of electromagnets 53, as will belater described. In order to maintain armature 55 spaced from theelectromagnets 53, when the latter are not energized, carriage membercarries arms 58 to which is attached coil spring 81, having its oppositeend connected to lever arm 58, which is fixed to armature 65. Thetension of spring 51 can be ad- 20 justed by the screw and boltarrangement 59, so that when the electromagnets are deenergized, tapperbar 38 is raised above roll I5, as shown in Fig. 3, and the armature 65will be positively held spaced from electromagnet 53, and yet will 2n bereadily attracted thereto upon energization of the electromagnets, tocause arms and 3l, and tapper bar 38, to move downwardly against stopmembers 45, whereupon the inertia of arms 31 and bar 38 will carry theseelements downwardly .'m momentarily against the tension of springs 39,so that tapper bar 38 will strike the projection I9 of roll I5, and thusmark record sheet 59.

Tape rolls 44 are constantly rotated through a suitable geararrangement, not shown (which also reverses their rotation to change thedirection of movement of the tape 10), by means of an electric motor 1I,carried upon transverse frame member 32. It will lbe seen that the copytape 10 extends from one of the tape rolls 44, laterally to spindles 42on one side of carriage 30, down under tapper bar 38 and longitudinallythereof, up the other side of carriage 38, over spindles 42, and back tothe other of tape rolls 44. Record sheet 59, which is marked during theoperation of the tapper bar 38, is carried upon a roll 12, rotatableabout a shaft 13, which is journalled at both its ends in plate members14, which are keyed to gear segments 58 so as to rotate shaft 13 andguide members 15 which extend transversely between plates 14, aboutshaft I8 upon the pulling of handle 50 to the left, as shown in Fig. 4.The record sheet is threaded from roll 12, over the top guide member 15,in between roll member I5 and tapper bar 38, thence to driving roll 15,which is driven at constant speed, through a suitable gear train 11, bymotor 18. In order to impart the motion of driving roll 15 to recordsheet 59, tension rollers 19, carried upon fingers 80, are resilientlypressed against roll 15 by means of coil springs 8|, which normally urgefingers 80 toward each other, to increase the friction between drivingroll 15 and record sheet 59.

An apron 52, extending transversely between and carried by end members II and I 2, guides the sheet 59 to the forward end of the recordingdevice I0, where it may be readily viewed by an operator, or cut off,without interference to the operation of the recording device. Theassembly of rollers and ngers 19 and 80 is readily removed fromfrictional engagement with driving roll 15 for the purpose of changingrecord sheets, since transverse supporting rod I4, `which carries thisassembly, is

swingable in an arc about pivots 84 by means of arms 85, which carry rodI4 and are pivoted about UUIUILL u 15, and a spring for urging thisplate against rollv 12, introduces sufficient drag upon roll 12 tomaintain the surface of record sheet 59 smooth and un- Wrinkled as ittravels beneath tapper bar 38.

In the bottom portions of Figs. 2 and 3 there are shown details or anovel photoelectric system of the present invention. vAs has alreadybeen described, light source 25 is rotated upon disc 24 at a constantspeed by means of motor 20 through the gear train shown. Brushes 88, ofany conventional type. coact with slip-rings 89 to carry.

current to the rotating light source from any suitable supply means suchas a battery |23 of Fig. 5. Also, 90 designates a means for focusinglight which is projected to the left as viewed in Fig. 2 andintercepted, in the absence of any opaque substance therebetween, by thephotoelectric cell,

29, which is mounted to be rotated upon disc 28 and driven through gears25, I1, I3, etc., and through the printing roll I by means of motor 20,at a speed synchronous with the rotation of the light source.

Brush 9| cooperates with slip-rings 92 to connect photoelectric cell 29with an amplifying and impulse generating circuit to be described later.Interposed in the path of light between source 25 and photoelectric cell29. is a frequency meter 93. having a pointer 94 which is adapted, aswill be described later, to vary in accordance with received radiosignals. Pointer 94 carries, at its outer extremity, a small flag member95 which is movable along with pointer 94 in an arc through which lightis projected during a portion of a cycle of rotation of light source 25.Meter 93 is carried within an opaque casing 95, which in turn, isrotatably mounted upon shaft 91, supported by pedestal member 98, uponbase member I3 to which the pedestal member 98 is securely fixed.Apertures 99 and |90 in casing 96 permit light to traverse the casing,and aperture S9 is tapered at one end, as indicated at lili of 3, for apurpose to be described later. Pedestal member 98 has an integralsupporting portion |02 which carries a Worm gear |03, in suitablebearings |94,

as well as a wheel |95 which meshes with worm |03. A dial |05 is rigidlyconnected to the shaft; carrying worm gear |93 for rotating meter casing96 through a pulley, not shown. rotatable with wheel |05 which transmitsrotation to casing 9S by virtue of the endless belt |01. Current foroperating meter 93 is introduced thereto by means of terminals |08 whichconnect with any suitable leads to a radio receiver= as will bedescribed later.

A diagrammatic representation of the recording device is shown in Fig.5, in which |99 represents a radio antenna of any suitable type, such asa dipole, connected to the input of a radio receiver ||0, which istunable to the carrier frequency of the radiosonde described in thebeginning of the specication. This receiver may be of any type, such asa superheterodyne, having an audio-frequency output which is connectedto frequency meter 93, having a movable pointer 94. As the radiotransmitter sends forth signals at audio-frequencies depending upon thedifferent atmospheric conditions being measured, pointer 94 of meter 93is movable through an arc of approximately degrees. A motor 20, drivenby any suitable source, not shown, rotates a disc 24 which carries alight source, such as lamp 25, and drives, through suitable gearing,heretofore described, a printing roll |5 with its helical pro# jectionI9 thereon. The other end of roll |5 drives through suitable gearing,also heretofore described, a disc 28, carrying photoelectric cell 29.Light source 25 may be energized through slip-'- rings 89, as shown, byan electrical source, such as battery |23. Since the gear'trains at eachend of printing roll I5 are made to have the same value, it is apparentthat discs 24 and 28 will be rotated synchronously, and if lamp 25 andphotoelectric cell 29 are initially adjusted to be in the samehorizontal plane, then the light from the lamp 25 will be directed tophotoelectric cell 29,

'at every point in the circle through which both are rotated, and thelight will be intercepted only at those points at which opaque objectsare interposed. Assuming that the only opaque object is the pointer 94,then light will he interrupted at one point in each revolution of discs29 and 24, which point may vary, depending upon the position of pointer94. In actual practice, the casing 9B of meter 93 also will interruptthe light, but this has no effect on the operation of the recorder., aswill be explained later. The output of photoelectric cell 29 isconnected by a suitable slip-ring 92 to the vacuum tube amplifier |25.which may be of any conventional design, capable of amplifying theminute currents of the photoelectric cell. The output of the vacuum tubeamplifier is connected to the grid |26 of the gaseous triode |21 whichmay be of the type commonly known as thyratron The anode |28 isconnected through a conductor |29 to the coils of electromagnets 63,thence through conductor 13| and resistor |32 to the positive pole of asource of potential which may be the conventional B battery. Thenegative pole of the B battery is connected to ground completing acircuit through conductor |33, to the cathode |34 of tube |21..

This circuit also includes a condenser |35, which has a function thatwill be described below.

It is a Well known characteristic of thyratrons that the conductancedoes not change directlyA with grid potential, but that upon the gridat-A taining a certain definite positive potential, ionization of thegas causes the anode-cathode conductance through the tube to increaseimmediately to its maximum value. Once the current ow has been startedby the grid, the latter has no further control and removal of gridpotential does not affect the anode-cathode current flow. The currentflow can be stopped,

however, by removing the anode potential for a slight interval, duringwhich the gas de-ionizes. After current flow has been stopped for thedeionizing interval, full anode potential can be reapplied and the tuberemains non-conductive until the grid reassumes its predeterminedignition potential, starting another cycle of opera tion similar to thatjust described.

The vacuum tube amplifier |25 is so designedthat it impresses aninstantaneous positive potential upon grid |26 upon sudden restoration'diately discharges and an impulse of current flows through theanode-cathode circuit, including tapper bar magnets 63, momentarilyenergizing them and actuating tapper bar 39. At the same time, thedischarge of tube |21 causes the condenser |35 to discharge because ofthe low impedance of the anode-cathode circuit across its plates. Thepotential is thus removed from anode |28, allowing the tube to de-ionizeand be ready for the next impulse of grid current. Upon removal of anodepotential, condenser |35 is recharged through resistance |32, which isof such value as to recharge the condenser in a predetermined interval.It will be seen, therefore, that in every cycle of rotation of lamp andphotoelectric cell 29, there will be an impulse of potential on grid|26, causing actuation of tapper bar 38 during the momentary dischargeof tube |21, and this impulse will occur immediately upon the suddenrestoration of the light beam immediately after it has been interruptedby the opaque flag 95 of pointer 94. I'he record printed upon sheet 59will be a series of dots, marked laterally upon the sheet, dependingupon the time in each cycle of rotation of the photoelectric system thatthe tapper bar 38 is attracted by electromagnets 63 and caused to strikeagainst helical projection I9.

Since the opaque casing 96, in actual practice, interrupts the beam oflight Just as does pointer 94, or its flag member 95, it is necessary toprevent operation of the tapper bar upon restora tion of the light beamafter it has been interrupted by casing 96, and before it has beenrestored after interruption by pointer 94. Ampliiler |25 has beendesigned so that only sudden (as distinguished from gradual),restoration of the light beam to its full value will cause actuation ofthe thyratron circuit. Since such design is conventional in the art, itis not discussed here. The gradual restoration of the light beam, afterinterruption, is not suilicient to impress the necessary positivepotential upon grid |26 to ignite the thyratron |21. After the lightbeam has been interrupted by the opaque portion of casing 96, it isrestored as the beam swings through the arc including aperture 99, whichis tapered as IDI, so that the light beam,

as it enters the aperture, is restored very grad' ually from the pointof convergence of the tapered portion |8| to the point at which theaperture has its maximum width, which is greater than thecross-sectional trace of the light beam in the plane of the aperture. Itwill be seen, therefore, that at only one point will the tapper bar 38be energized, and this point will be immediately after the light beamhas been interrupted by ilag member 95 of pointer'94.

By means of the worm and wheel |03, |04, and

the dial |06 for actuating the same, meter casing 96 can be rotatedthrough endless belt |01, to move the entire meter assembly, includingpointer 94, for calibrating purposes. When the recording device is firstinstalled, the position of pointer 94 for different indications receivedfrom the radiosonde mentioned earlier in the specication, may becompared with a calibrated frequency meter and any slight differencebetween the minimum and maximum frequency values of the meter can becompensated by movement of the meter casing.

As stated above, for every revolution of discs 24 and 28, there will bean actuation of tapper bar 38, corresponding to th'e point in the cycleof rotation at which pointer 94 is interrupted by the light beam. It hasbeen found that 4a favorable range of frequencies radiated from theradiosonde and indicative of humidity, temperature, pressure, etc. isabout 5 to 80 cycles per second. If frequency meter 93 were capable ofindicating throughout 360 degrees, and if it were possible to makeaperture 99 extend through 360 degrees of arc, then for every rotationof discs 24 and 28, only one rotation of printing roll I5 would berequired, in order that tapper bar 38 might be able to strike projectionI9 at any point through its length. As a practical matter, however,meter 93 is restricted to an indicating arc of degrees. If printing rolll5 is revolved only once for every revolution of discs 24 and 28, thenthe portion of printing roll that could be utilized in the making of arecord would be only one-fourth its complete length, since for every 360degrees of disc rotation there would be only a 90 degree interval inwhich pointer 94 could cause operation of tapper bar 38. The gear train11, above described, is therefore, made of such value that for everyrotation of discs 24 and 28, printing roll I5 will make four completerevolutions. Thus, the printed record can be spread completely acrossthe width of printing roll l5. While 90 degrees seems a desirableindicating range for meter 93, it has been found that meters can be usedin other ranges of arc, such as degrees. For purposes of description,however, it can be assumed that the meter indicating range is 90 degreesof arc.

While only one embodiment of the invention has been illustrated anddescribed, it will be understood that many changes may be made withoutexceeding the scope of the present invention. It is, therefore, notintended to limit the invention to the particular embodiment described,but only by the scope of the appended claim.

I claim:

A recording device comprising an indicator of variable quantities,having a pointer movable through a deilnite arc and an opaque casinghaving a transparent portion for the arc through which said pointer ismovable, a light source and a photoelectric cell synchronously rotatedat spaced points about the same axis, said pointer' of said indicator,upon interception by said pointer, the value of the quantity thusrecorded being dependent upon the angular position ofV said pointer inits arc of travel.

RALPH R. CHAPPELL.

